Hi everyone, I have 2 rows of 5 600w hid lights. I have a carbon filter at the beginning of each row then a 10 in. 700cfm fan then the 5 air cooled hoods in a row then vented outside. I am thinking of moving the fan so it is just before the outside exhaust hole or should I just add another fan? Would it also have to be a 700cfm fan? Also do I need to put a speed controller on my fans? What is their purpose? I am also thinking it might be a good idea to put backdraft dampeners in the ducting to keep bugs etc.. from coming into the room when the fans are off or would they restrict my airflow. Also just read that it is not good to draw the heated air from your lights thru your fan. I wouldn't have thought this would be a problem. I also have a 3ton A/C unit in the room. Thanks in advance